In recent years, a radiation monitor has been proposed which is provided in facilities that treat a radioactive material, such as nuclear power plants and hospitals, and measures surface contamination due to a radioactive material adhering to the hand, foot, and clothes of the worker in the facilities. The radiation monitor measures radiation emitted from the radioactive material, sounds the alarm when the measured value is more than a warning level, and displays a contaminated part on a liquid crystal display.
In the radiation monitor, a hand monitoring unit is provided with a hand insertion portion into which the hand of the examinee is inserted and a pair of radiation detecting units is provided on the side surfaces of the hand insertion portion that face each other. The surface contamination of the hand can be measured as follows. The examinee opens the left and right hands and inserts the hands into the hand insertion portions. Then, radiation that is emitted from the radioactive material adhered to the surface of each of the palm and back of the hand of the surface is detected (for example, see Patent Document 1).